Colored contact lenses have been used to modify or enhance the color of a wearer's eyes. In general, there are two classes of colored contact lenses. The first class of colored contact lenses are those which use essentially transparent enhancement colors that combine with the color of the natural iris to produce a new appearance. Such tinted lenses typically are used to turn a hazel eye to an aqua colored eye. This class of colored lenses may not be able to change an underlying dark colored, brown iris to blue. The second category is the class of opaque colored lenses having a continuous opaque pattern that fully covers the iris or having an intermittent opaque pattern that partially covers the iris. Opaque colored contact lenses can effectively and substantially modify the wearer's eye color.
Opaque colored contact lenses, which can provide a natural appearance, can be produced by directly printing a colored image with an ink including pigment particles to the surface of a preformed contact lens. However, opaque colored contact lenses made according to this technique can have pigment particles protruding outwardly from the lens surface and may impart wearing discomfort when being worn by a user.
To reduce such wearing discomfort, opaque colored contact lenses are can be advantageously produced by first printing a colored image with a pigment-containing ink on a molding surface of a mold for cast-molding of a contact lens, dispensing a lens-forming composition in the mold with the colored image printed on one of the molding surface, and curing the lens-forming composition to obtain a cast-molded contact lens with the printed colored image which is transferred from the molding surface to the cast-molded contact lens during the curing process. Although opaque colored contact lenses made according to this technique can have pigment particles embedded in the lens surface (i.e., not protruding outwardly from the lens surface) but still being exposed, the printed area (i.e., particle-exposing areas) on the surface of the opaque colored contact lenses would have a roughness much higher than that of the non-printed areas. The higher roughness in the printed area on a lens surface may still impart wearing discomfort.
In order to reduce the roughness, it has been proposed to apply a clear coat (i.e., a layer of a polymerizable composition which can be either a lens-forming composition or any polymerizable composition free of any colorant onto a molding surface of a mold), and print a colored image with a pigment-containing ink onto the clear coat on the molding surface. However, the print quality can be severely degraded by the clear coat, due to loss in print intensity and increased smearing.
Therefore, there are still needs for a process for producing opaque colored contact lenses which can provide enhanced wearing comfort to users and for such opaque colored contact lenses.